Meals consumed at fast-food restaurants are often seen as one of the biggest contributors to the obesity epidemic. But according to a new study in the Journal of the American Academy of Nutrition and Dietetics, 92 percent of 364 measured restaurant meals from both large-chain and non-chain (local) restaurants exceeded recommended calorie requirements for a single meal. In 123 restaurants in three cities across America, the research team found that a single meal serving, without beverages, appetizers, or desserts sometimes exceeded the caloric requirements for an entire day.

"These findings make it clear that making healthy choices while eating out is difficult because the combination of tempting options and excessive portions often overwhelm our self-control," said senior author Susan B. Roberts, Ph.D., director of the Energy Metabolism Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts University in Boston.

"Although fast-food restaurants are often the easiest targets for criticism because they provide information on their portion sizes and calories, small restaurants typically provide just as many calories, and sometimes more. Favorite meals often contain three or even four times the amount of calories a person needs, and although in theory we don't have to eat the whole lot in practice most of us don't have enough willpower to stop eating when we have had enough," Roberts continued.

The study was conducted by researchers at the HNRCA and the Friedman School of Nutrition Science and Policy at Tufts University and colleagues, who analyzed the calorie content of frequently ordered meals in both local restaurants and their large-chain equivalents in three separate locations: Boston, San Francisco and Little Rock, Ark. The data were collected between 2011 and 2014 by comparing the meals against human calorie requirements and USDA food database values. The cuisine studied by researchers included American, Chinese, Greek, Indian, Italian, Japanese, Mexican, Thai and Vietnamese fare.

The study also found that American, Chinese and Italian had the highest calorie counts with a mean of 1,495 calories per meal.

"Oversize servings lead a lot of dieters to avoid most restaurants entirely, or stick to items like salads that they know are served in reasonable portions," said co-author William Masters, Ph.D., professor of food economics at the Friedman School. "Standard meals are sized for the hungriest customers, so most people need superhuman self-control to avoid overeating. There is a gender dimension here that is really important: women typically have a lower caloric requirement than men, so on average need to eat less. Women, while dining out, typically have to be more vigilant."